verb (patrols, patrolling, patrolled)

Keep watch over (an area) by regularly walking or traveling around or through it:the garrison had to patrol the streets to maintain order [no object]:pairs of men were patrolling on each side of the thoroughfare

Origin

The unpleasant side of military life is brought to the fore by patrol. It comes, via German, from French patrouille, from patrouiller ‘paddle in mud’. This in turn was formed from patte ‘paw’ and dialect (gad)rouille ‘dirty water’.